There are no more files

Hi
I have been struggling with this problem for a while:
I have two Asus K50IJ Laptops running Window 7 Home Premium 64b, both of which are experiencing the same problem, and started about the same time.

Basically, I am unable to save any files to the local drives on the machines (I can save to a network drive). The message I receive on a pop-up dialogue box is: "There are no more files". On one of the laptops I have received a different message this morning "Latest news....htm There are no more files."

I have searched various help forums on this problem and although there seems to be some other people experiencing it, no-one seems to have come up with a solution yet.
On one laptop, I have done a re-install of Windows on the operating system partition from the manufacturers recovery partition. I was hoping this would work but the problem still exists.

It is strange how it happened on both machines (same model, same age, purchased together) at the same time, this makes me think its either a virus transmitted through our network, or a windows update problem. I have run virus scans though with nothing found.

Please can anyone help?
M